Improvement And Application Of Carbide Slag Desulfurization

Based on the principles of "adaptating local conditions, treating was tes and changing them into valuables, and developing cyclic economy", it is to utilize the carbide mud residue as the desulfurizing agent to rep lace the limestone to achieve the multipurpose use of wastes. At present, the flue gas desulfurization process of our country mainly adopts the li mestone-gypsum wet desulphurization, the process is relatively simple an d in stable and reliable running, but the price of limestone desulfurizing agent is high, the running cost accounts for about 30-35% of the desul furizing installation, in order to enhance the running economic benefit o f power plant and reduce the running cost, it is considerably necessary to replace the limestone based process with the carbide mud residue pro cess, for desulfuration of replacing the limestone with carbide mud resid ue, on the one hand, it can reduce the calcium carbide waste residue di scharge largely, reduce the environmental pollution, and obtain good env ironmental benefit; on the other hand, it adopts the low price desulfurizi ng agent, reduces the running cost, and at the same time it reduces min ing limestone mine, reduces the consumption of limited resources, gives effective protection to the limestone mineral resources, and at the same time it also reduces the CO2 emission of the limestone-gypsum wet de sulphurization process, which obtains economic benefit, and at the same time obtains good environmental benefit and social benefit.With comparing the existing condition of the existing flue gas desu lfurization technology, for taking full advantages of local characteristics t o make cyclic utilization to the carbide mud residue of enterprises and adopting carbide mud residue-gypsum process for flue gas desulfurizatio n, it has the merit of treating wastes and changing them into valuables, and it will reduce the pollutant emission, and at the same time reduce the production and running cost.After adopting the carbide mud residue-gypsum wet desulphurization technological line, according to the contents of sulfur dioxide in the fl ue gas, it designs the desulfurizing column, and establishes strict operati on procedures, such as the gas-liquid ratio and the flue gas flow velocit y. At the same time, through passing the produced calcium sulfite into t he air for forced-air-oxidation to produce calcium sulfate, and using the slurry pump to make pumping from the bottom of the desulfurizing co lumn, after double-stage dehydration, it can obtain the desulfurized gyps um with 10% moisture.The improvement project has two stages for its execution, the first stage is to newly add one layer of trays under the first layer of sprayin g of the existing two the 1# and 2# absorbing columns, and make reco nstruction to the first and the second layers of spraying pipes and nozzl es, and add an acid liquor gathering unit in the absorption column, to g ather the acid liquor into the oxidation column; for the second stage rec onstruction, it is to newly build a 3# absorption column, the 3# absorpt ion column adopts the form of three layers of spraying (the upper most layer is intensive spraying) plus one layer of trays, after the 3# absorp tion column putting into service, it is to switch the flue gas into the 3# absorption column in turns, and then make reconstruction for the two old absorption columns respectively, to reconstruct the third spraying of each old absorption column into one layer of intensive spraying.After reconstruction, for the first stage, under the precondition of th e density of SO2 at the inlet of FGD being≤2000 mg-Nm-3 (the total s ulphur content of the used raw coal being≤0.8%), the density of SO2 at the desulfuration outlet is reduced to be≤50 mg-Nm-3. For the new and old absorption columns of the second stage, under the precondition of the density of SO2 at the inlet of FGD being≤3500 mg-Nm-3 (the t otal sulphur content of the raw coal being≤1.5%), the density of SO2 at the desulfuration outlet is reduced to be≤50 mg-Nm-3 the desulfura tion efficiency reaches 98.6%, and meets the required environmental ind exes.In the end, it states the running conditions of this time of improve ment project for desulfuration, with calculation for the production and r unning costs and the reduced sulfur dioxide emission, it shows that the annual saved cost is about 8.80 million yuan compared with the limesto ne based process, and the sulfur dioxide emission reduces 841.5 t·a-1, so the carbide mud residue as a desulfurizing agent has good economic be nefit and environmental benefit.